Continuous drier for wet granular material



Oct. 24, 1939.

w. H. GOLDEN CONTINUOUS DRIER FOR WET GRANULAR. MATERIAL Original FiledJune 24, 1937 INVENTOR. WIN/am H Go/Jen 714;.

A TTORNEYS.

Patented a. 24, 1939 PATENT OFFICE CONTINUOUS DRIER FOR WET GRANULARMATERIAL 2 William H. Golden, Pittsburgh, Pa.

Application June 24, 1937, Serial Ne. 150.048 Renewed September 19, 19399 Claims.

This invention relates to driers for wet granular material such as wetsand and the like, and more particularly to driers adapted forcontinuous operation. Objects of the invention are ,5 to provide a drierof this nature which will provide a more intimate heat exchange contactbetween the sand or other material to be dried and the heating medium,and which will have a higher drying capacity than other devices of thisnature now in use.

A further object of the invention is to provide a drier which will bringthe sand or other material to be dried in contact with heated surfacesin the form of a number of relatively thin films thereby promotingdrying speed and permitting the ready escape of water vapor from thematerial.

A still further object of the invention is to provide a drier which issimple in construction, 20, efiicient in operation, and in which thedrying elements consist of a number of superposed trays which areinterchangeable and readily replaceable. Further objects will becomeapparent from the following description and will be 0 pointed out in theclaims appended thereto.

With the above and other objects in view, the invention consists in thenovel combination and association of parts as will be hereinafter moreparticularly described, reference being had to the accompanying drawing.

In the drawing;

Fig, 1 is a vertical section showing the assembly of a drier constructedin accordance with the invention.

Figs. 2, 3 and 4 are horizontal sections on the lines XX, YY, and ZZ,respectively, of Fig. 1, looking in the direction of the arrows. Fig. 5is a detail section taken on-the line 55 of Fig. 3 showing one of thedrying trays.

.Referring to Fig. 1, the drier includes a furnace 5, having a centralflue 2, and plurality of spaced side flues 3, the whole constituting anassemblyfor the generation and transmission of heat. The furnace I maybe a coal burner as shown, but it may be readily adapted for thecombustion of wood, oil, or gas without departing. from the scope of theinvention. In the modification shown the furnace consists of asupporting base 4, an ash box 5, provided with an opening 6 for theremoval of ashes and preferably fitted in the usual manner with an ashdoor having an air register and a top flange 1 supporting a grate 8. Thefire box consists of a cylindrical side wall 9, which may be lined withinsulating brick and which is provided with an outwardly extendingflange ID at the lower edge thereof for a purpose which willsubsequently be described. A firing door H is fitted into the side wallin the usual manner but is fitted with 60 a firing collar l2 extendingsome distance away from the furnace to keep the sand or other materialto be dried out of the fire box.

The furnace I, whether of the coal, oil, or gas fired type is providedwith a fire box dome or top l3 which is seated on the cylindrical side 5wall and is provided with the central flue 2 and the side flues 3, whichare preferably four in number, spaced at angles of 90. In themodification shown, the dome I 3 is a separate casting, and is fittedwith flanges M to make a gastight fit with the side wall 9 and the fluesare cast integral therewith. The central flue 2 is relatively short andhas a level upper edge, while the side flues 3 are beveled toward thecentral flue and provided with notches 4 for a purpose which willsubsequently be described.

The drying trays which are mounted above the furnace in superposedrelation constitute one of the features of the invention, since theyoperate to bring the sand or other material to be dried into closecontact with the flues containing the hot gases from the furnace. Eachtray consists -'as shown in Fig. 5 of an inverted frustro-conical bell15 which is preferably of cast metal, the bell having a peripheral zoneconsisting of a heat conducting flange I6 with openings I! therein and acentral zone, which is also preferably provided with additional openings18 and which has a plurality of vertical flue pipe sections I9 castintegral therewith. In the top of each flue pipe section I!) is a smallvent 2| which is of the order of 0.5 sq. in. in cross-section and whichprovides communication between the interior of the flue and the spacesbetween the drying trays. Similar vents may be provided in the centralflue pipe sections 20, although they are not shown on the drawing.

Reference to Fig. l of the drawing will show that the various sectionsare supported upon each other when the drier is assembled so that anysection may be removed and a new one replaced with a minimum of time andeffort. Similarly, the drier may be provided with any number of dryingtrays to suit the requirements of any given sand or other material to bedried and the extent to which the moisture must be removed.

It will be noted that the peripheral openings I! are larger than thecentral openings l8, thereby promoting the continuous movement of thesand or other material from the periphery of the trays to the centralzone and causing it to be heated in thin films which promotes a readyescape of the steam or water vapor between the trays and through thevents 2| in the flue pipe sections 19.

The various drying tray sections are covered by a top flue piece 25,which is in the form of a spider seated on the top flue pipe sections asat 26 and having beveled edges to correspond there- With. The arms ofthe spider which constitute continuations of the flue pipe sectionsconnect them with a stack 21, preferably provided with a damper 28, andthus serve to collect all the hot gases from the furnace l.

The entire drier assembly is surrounded by a vertical shell 30 which issupported by a perforated ring 3| seated on the flange II] at the bottomof the furnace wall. This shell serves to retain the sand and conductthe dried sand downwardly around the wall 9 of the fire box and throughopenings 32 in the ring v3! and away from the drier.

The operation of my improved drier will be apparent from the abovedescription. Sand is shoveled into the top of the drier, and isdistributed over the top bell by the arms of the spider 25. The sandtravels by gravity over the surface of the top drying tray and fallsthrough the openings 17 and 8 onto the second tray in the form ofrelatively thin streams, the moisture,

being removed by the heat of the tray and of the flues i9 and 26 aroundwhich the sand is caused to pass. The sand drops by gravity from tray totray, losing moisture in each passage over the hot metal. The openings Hand 18 are preferably made smaller in the lower trays than are thecorresponding openings in the upper trays, and are sized so that thebells or trays do not completely fill with sand. The openings 2!, beingat the tops of the flue sections always remain uncovered so thatmoisture evaporated from the sand will pass into the combustion gasflues and will be carried away with the combustion gases therein. Byreason of the inclined surfaces of the trays and the heat conductingcapacity of the flanges IE, only dry sand can come into contact with thetop or side walls of the furnace l, and so these parts are protectedfrom warping or cracking.

From the above it will be seen that the invention provides a drier whichis both simple and efficient in operation. I have found by actualcomparison that the drier of the present invention will remove the sameamount of moisture from more sand than will other driers of equal sizethat are now on the market.

What I claim is:

1. A continuous drier for wet granular material comprising incombination a plurality of superposed, inverted frustro-conical dryingtrays, openings near the periphery of each tray to permit the gradualdownward passage of the granular material from tray to tray, and avertical heating conduit passing through the central zones of saidtrays.

2. A continuous drier for wet granular material comprising incombination a plurality of superposed, inverted frustro-conical dryingtrays having graduated openings therein of a size to permit the gradualdownward passage of the granular material from tray to tray, a shellsurrounding said trays, and a plurality of vertical heating conduitspassing through the central zones of said trays.

3. A continuous drier for wet granular material comprising incombination a plurality of superposed, inverted frustro-conical dryingtrays, openings near the periphery of each tray to permit the gradualdownward passage of the granular material from tray to tray, a verticalflue for hot gases passing through the central zones of said trays, andvents in said flue be tween each pair of trays to permit water vaporevolved from the granular material to pass into 4. A continuous drierfor wet granular material comprising in combination a plurality ofsuperposed, inverted frustro-conical drying trays having graduatedopenings therein 01' a size to permit the gradual downward passage ofthe granular material from tray to tray, a shell surrounding said trays,a plurality of vertical flues for hot gases passing through the centralzones of said trays, and vents in said flues between each pair of traysto permit Water vapor evolved from the granular material to pass intothe flue.

5. As an article of manufacture, a drying tray comprising an invertedfrustro-conical bell of cast metal, said bell having a peripheral zoneconsisting of an apertured heat-conducting flange and a central zonehaving openings therein and a plurality of vertical flue pipe sectionscast integral therewith.

6. As an article of manufacture, a drying tray consisting of an invertedfrustro-conical bell of cast metal, said bellhaving a peripheral zoneconsisting of a heat conducting flange with openings therein and acentral zone having openings therein and a plurality of vertical fluepipe sections cast integral therewith, each pipe section having anotched upper edge that terminates in a plane parallel to the plane ofthe bell at its base.

7. A continuous drier for wet granular material comprising a pluralityof drying trays, each tray comprisingan inverted frustro-conical bell ofcast metal havinga peripheral zone consisting of a heat conductingflange with openlugs therein to'permit the passage of the granularmaterial and a central zone having openings therein and a plurality ofvertical fluepipe sections surrounding said openings, each pipe sec tionhaving a notched upper edge that terminates in a plane parallel to theplane of the bell at its base and forms a supporting seat for the trayabove it, and a top flue piece comprising a spider seating on the topflue pipe sections and connecting them with a stack.

8. A continuous drier for wet granular material comprising incombination a furnace for the'generation of hot gases, a, plurality ofvertical lines in the top of said furnace, a plurality of superposed,inverted frustro-conical drying trays surrounding said flues, openingsnear the periphery of each tray of a size to permit the gradual downwardpassage of the granular material from tray to tray, vents in said fluesbetween said drying trays, and a spider seating on the tops of saidflues and connecting them with a stack.

9. A continuous drier for wet granular material comprising incombination a furnace including a cylindrical side wall, having anoutwardly extending flange at the bottom thereof, a perforated ringseated on said flange, a cylindrical shell supported on said ring, a topfor the furnace seated on the cylindrical side wall thereof and providedwith a central flue and a plurality of spaced side flues having notchedupper edges which are beveled toward the central flue, a plurality ofdrying trays comprising inverted frustro-conical bells seated upon saidflues, each bell having graduated openings therein and notched fluesections in alignment with the flue sections of the furnace top, and acollecting spider surmounting the top flue sections and connecting themwith a stack.

WILLIAM H. GOLDEN.

